Coupling element for a coupling for connecting pressure medium lines

ABSTRACT

The invention relates to a coupling element (1) for a coupling for connection of pressure medium lines, including a housing (2), a flow channel (5) for a pressure medium, a valve tappet (6), a pressure sleeve (7), and an inner body (8), wherein the valve tappet (6) has a valve tappet head (10), wherein the pressure sleeve (7) surrounds the valve tappet (6), wherein the pressure sleeve (7) is held such that it can move along the coupling axis A between a closed position and an open position, wherein the pressure sleeve (7) is in contact with the valve tappet head (10) in the closed position thereof, whereby a force parallel to the coupling axis A acts upon the valve tappet head (10) from the pressure sleeve (7). The safety for users and the operating characteristics are improved, in that the inner body (8) and/or the pressure sleeve (7) have means with which the force from the pressure sleeve (7) acting on the valve tappet head (10) can be limited.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a 35 U.S.C. § 371 national phase application of PCTInternational Application No. PCT/EP2016/077528, filed Nov. 14, 2016,which claims the benefit of priority under 35 U.S.C. § 119 to GermanPatent Application No. 10 2015 222 640.9, filed Nov. 17, 2015, thecontents of which are incorporated herein by reference in theirentirety.

FIELD OF THE INVENTION

The invention relates to a coupling element for a coupling, inparticular a hydraulic coupling, for connecting pressure medium lines.Furthermore, the invention relates to a valve tappet for a couplingelement.

Coupling elements for couplings, in particular for hydraulic couplings,are known in the state of the art in a plurality of designs. Hydrauliccouplings, specifically a combination of a coupling sleeve and acoupling plug, serve to connect two sections of a pressure medium line,and are often used to connect hydraulic equipment to a hydraulic source,for example to connect a tool or accessory to a farming machine orconstruction machine.

Coupling elements in which the flow channel is sealed by a centralpressure sleeve, in that the pressure sleeve is in at least indirectproximity to the valve tappet head of the valve tappet when in itsclosed position, are known in the state of the art. Here a seal islocated between the valve tappet head and the pressure sleeve.

EP 1 273 844 B1 provides an example of this type of hydraulic couplingwith a coupling element in which a pressure sleeve for closing a flowchannel abuts on the valve tappet head of a valve tappet. The pressuresleeve is spring-loaded in the direction of its closed position andworks together at least partially with a seal with the valve tappethead.

In order to open the flow channel in accordance with EP 1 273 844 B1,the pressure sleeve is moved out of its closed position in the directionof its open position, for example by means of a coupling plug insertedinto the coupling sleeve, whereby the flow channel is opened. Movementof the pressure sleeve from its closed position into its open positionalways takes place against the force of the spring which holds thepressure sleeve in its closed position. In the closed position, thepressure sleeve fits against the valve tappet head and exerts a force onthe valve tappet parallel to the coupling axis of the coupling element.This force includes, among other factors, the spring load on thepressure sleeve and the pressure-dependent forces on the pressure sleevein the direction of its closed position.

The coupling elements known in the state of the art present the riskthat, under very high pressure, especially upon reaching the burstingpressure of the coupling element, parts of the coupling element can comeloose or tear away, which constitutes a safety hazard for individualsstanding nearby.

The invention presented here must therefore solve the problem ofproviding a coupling element and a valve tappet which offer increasedsafety to the user while simultaneously preserving or improving theoperating characteristics of the coupling element.

INTRODUCTORY DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The aforementioned problem is solved with another coupling element ofthis type in that the inner body and/or the pressure sleeve exhibit afeature by which the forces acting upon the valve tappet head from thepressure sleeve can be limited. “Limited” in this context means not onlyan absolute limit to a fixed threshold value, but also a percentagereduction of the force.

The coupling element is a part of a coupling, in particular a hydrauliccoupling, for connecting pressure medium lines and can consist of acoupling sleeve or a coupling plug, for example. A coupling therebyincludes a coupling sleeve as well as a coupling plug whereby thecoupling plug is inserted into the coupling sleeve in order to connectthe flow channels of the coupling sleeve and coupling plug with eachother. The coupling element preferably has a nominal width of 19, 16, or12.5 mm.

The coupling element can be connected with a corresponding secondcoupling element by use of, for example, a screw connection or snapconnection. The coupling element includes a housing, a flow channel fora pressure medium, a valve tappet, a pressure sleeve, and an inner body.

The housing of the coupling element exhibits a central coupling axis A,which runs from a first end of the coupling element, to which a pressuremedium line can be connected, to a second end, at which the connectionwith another coupling element is made. It is preferential that thecomponents of the coupling element are rotationally symmetrical aroundcoupling axis A. For example, the inner body or in the case of acoupling sleeve the inner body is rotationally symmetrical andsleeve-like in form. Furthermore it is preferential that motion of themovable components of the coupling element takes place parallel tocoupling axis A.

In particular, the housing limits at least a part of the flow channel,whereby it is favorable that the continuing course of the flow channelis limited by additional components of the coupling element. Forexample, the flow channel is limited at least by the housing, the innerbody, and the pressure sleeve.

Preferably, the housing exhibits a connecting component and a slidingsleeve. The connecting component is preferably screwed into a base body,whereby the base body simultaneously fixes the inner body to theconnecting component. The base body is also preferably sleeve-like inform. Advantageously, a seal is placed between the inner body and theconnecting component, especially on one abutting face of the inner body.The external sliding sleeve is retained on the base body and can slidebetween an open position and a retaining position. The base body in turnsurrounds the inner body.

Preferably, a number of recesses exist within the base body, into whichretaining elements, in particular retaining balls, are located. In anopen condition, the retaining elements are located in the recesses ofthe base body and work together with an associated insidecircumferential groove in the sliding sleeve, so that the sliding sleeveis held positively in its open position. Between the base body and thesliding sleeve, a sleeve spring for example may be placed, which pressesthe sliding sleeve in its open position against the retaining elements,in the direction of the locked position. Further motion of the slidingsleeve is prevented by the retaining elements in this condition. Thecoupling element additionally includes a piston which rides inside thebase body and prevents motion of the retaining elements when the slidingsleeve is in open position.

When the piston is pushed in the direction of the inner body, forexample due to the introduction of a corresponding second couplingelement into the first coupling element; for example a coupling pluginto a coupling sleeve; from a certain position of the piston, theretaining power of the retaining elements is taken on by an area of thesecond coupling element, until the retaining balls can recede into anoutside circumferential groove in the second coupling element. In thismoment, the locking sleeve, which is now free to move, is pressed intoits locking position by the sleeve spring, whereby the retainingelements are subsequently blocked by a keepout area of the slidingsleeve. The sliding sleeve thereby moves until it contacts a blockingelement located on the base body, locked position of the sliding sleeve.The retaining element could consist of a circlip placed on the outercircumference of the base body, for example.

In order to separate the coupling elements of a coupling which areconnected in this manner, the sliding sleeve must be manually moved intoits open position against the force of the sleeve spring, whereby theretaining elements can once again recede into the inside circumferentialgroove of the locking sleeve, and thus enable the separation of thesecond coupling element.

The valve tappet is held within the coupling element in such a mannerthat the valve tappet is centrally aligned in the flow channel.Consequently, the flow channel surrounds the valve tappet which islocated within the canal, so that the pressure medium flows around theshaft of the valve tappet and the valve tappet head when the coupling isin use. It is preferable that the valve tappet head is a part of theflat-sealing abutting face on the second end of the coupling element.

The valve tappet is located in such a manner that it is surrounded bythe inner body and the pressure sleeve. It is preferable that thepressure sleeve is located within the inner body, which is connectedwith the housing in either a fixed or floating manner, in such a waythat the pressure sleeve can be slid parallel to coupling axis A betweena closed position, in which the flow channel is sealed by the pressuresleeve, and an open position, in which the flow channel is opened by thepressure sleeve. A compression spring which exerts a force on thepressure sleeve in the direction of its closed position is particularlysuitable here, so that the pressure sleeve is always held in its closedposition by the compression spring.

In the pressure sleeve's closed position, a sealing of the flow channelis effected in that the pressure sleeve at least indirectly contacts thevalve tappet head. It is thereby envisioned that the pressure sleevedirectly, indirectly; for example with a seal; or partially directly andpartially indirectly contacts the valve tappet head. It is deemedpreferential to always have a seal between the pressure sleeve and thevalve tappet head. The seal could be placed in a circumferential groovein the valve tappet head, for example. It is preferable that the seal islocated on the inside circumference of the pressure sleeve.

The pressure sleeve is designed and located so that it contacts thevalve tappet head in such a manner that a force from the pressure sleeveparallel to coupling axis A acts on the valve tappet head. This forceincludes in particular the force of the compression spring acting on thepressure sleeve and the force components that result from the pressuremedium present under pressure in the flow channel, which acts on thepressure sleeve and exerts a force on the pressure sleeve in thedirection of the valve tappet head.

When pressure is applied in the closed flow channel, the valve tappet isthus loaded by the pressure acting against it, as well as by the forceapplied by the pressure sleeve. As pressure increases within the flowchannel, the shaft of the valve tappet can stretch due to the axialtension, which if the force on the valve tappet is not moderated canresult in the valve tappet head or the valve tappet tearing off in theregion of the shaft or in the region of the mounting area of the valvetappet.

In order to limit the forces exerted by the pressure sleeve upon thevalve tappet, particularly those parallel to coupling axis A, the innerbody and/or the pressure sleeve exhibit some apparatus by which thatforce can be limited. An example would be that this apparatus acts onthe inner body and/or the pressure sleeve in such a manner that theforce of the pressure sleeve upon the valve tappet head is limited, inthat at least a portion of the force from the pressure sleeve istransferred to the inner body. The force is transferred in turn from theinner body to the housing. Limiting this force dependably prevents thedestruction of the valve tappet and thus increases the operationalsafety of the coupling element.

In particular it is provided that the inner body and/or the pressuresleeve are constructed in such a way that they limit or reduce theforces acting upon the valve tappet head in at least one operating stateof the coupling element. For example it is imagined that beyond apredetermined threshold value of pressure within the coupling element,the force exerted by the pressure sleeve upon the valve tappet head islimited or reduced by these means.

Normal operating pressures for a coupling element are between 25 MPa and40 MPa, with specific operating pressure being 35 MPa. Preferentially itis intended that the predetermined threshold value for pressure withinthe coupling element, beyond which the apparatuses limit or reduce theforce, lies in the range between normal operating pressure and 4 timesnormal operating pressure, particularly between 1.5 and 2 times normaloperating pressure.

It is especially preferable that provisions are provided for limitingthe force of the pressure sleeve upon the valve tappet head for in theinner body as well as on the pressure sleeve. It is preferably providedthat the provisions are constructed and implemented in such a way thatthe means in the inner body and the features on the pressure sleeve worktogether to limit or reduce the force from the pressure sleeve upon thevalve tappet head.

It is advantageously provided that the features in the inner body and/orthe features on the pressure sleeve are constructed and implemented insuch a way that movement of the pressure sleeve in the direction of thevalve tappet head can be limited by said means.

The inventive coupling element exhibits the advantage of reducing therisk of overloading the valve tappet using these apparatuses, in thatthe force acting upon it from the pressure sleeve is limited by themeans in at least one operating condition, notably beyond at least oneoperating condition, whereby destruction of the valve tappet isprevented. With these features, the forces emanating from the pressuresleeve are distributed between the valve tappet head and the inner bodyby the apparatuses.

Additionally, the inventive coupling element exhibits the advantage thatthe same operating parameters as with known constructions, such asoperating pressure and bursting pressure, can be achieved using moreaffordable materials. Furthermore there is the advantage that using thesame materials as in known constructions can result in higher operatingparameters, and with higher-quality materials even greater operatingparameters.

In accordance with a first design of the coupling element, it isprovided that the apparatus in the inner body is designed as a firstlimit stop and the apparatus on the pressure sleeve as a second limitstop, whereby the first and second limit stops work together to limitthe force upon the valve tappet, in particular upon the valve tappethead.

Preferably, the pressure sleeve is guided within the inner body. Inorder to limit or reduce the force of the pressure sleeve upon the valvetappet head, a limit stop is provided for in the inner body as well ason the pressure sleeve. The first limit stop and the second limit stopcome into play in at least one operating state, in particular as of atleast one operating state of the coupling element, so that force can betransferred from the pressure sleeve to the inner body, whereby aportion of the forces exerted on the pressure sleeve in the direction ofthe valve tappet head is transferred by the first or second limit stopof the inner body, which is affixed to the housing. The force from thepressure sleeve upon the valve tappet is thereby limited, which isespecially advantageous in the case of high pressures within the flowchannel, especially pressures over and beyond operating pressure.

The first limit stop and the second limit stop can be implemented aslocal protrusions, for example, which emerge from the inner body or thepressure sleeve. It is preferable that a number of regularly distributedprotrusions are used, which constitute the first or the second limitstop.

A later iteration demonstrated that it is especially advantageous whenthe first limit stop is designed as a first shoulder on the inner bodyand the second limit stop is designed as a second shoulder on thepressure sleeve. It is advantageous to make the first shoulder on theinner body and the second shoulder on the pressure sleevecircumferential, so that an even distribution of force from the pressuresleeve to the inner body can be achieved around the entire circumferenceof both shoulders.

The first and second shoulders exhibit corresponding contact surfaces,so that the force from the pressure sleeve on the valve tappet islimited through contact between the contact surfaces. It is preferablethat the corresponding contact surfaces are in an orthogonal orientationto the coupling axis of the coupling element. The first shoulder islocated on the end portion of the inner body which is oriented in thedirection of the valve tappet head and preferably has a rectangularcross-section. It is advantageous to have an additional sealing shoulderin the inner body, and to include a seal between the first shoulder andthe sealing shoulder, which functions between an interior circumferenceof the inner body and an exterior circumference of the pressure sleeve.The first shoulder then serves on the one hand to absorb forces from thepressure sleeve and on the other hand as a stop for a groove for theseal.

The second shoulder is preferably located on the end portion of thepressure sleeve which is oriented in the pressure sleeve's openposition. As an example, the second shoulder has a rectangularcross-section. It is preferable that the second shoulder makes up atleast a part of the circular abutting face of the pressure sleeve whichis oriented in the direction of the pressure sleeve's open position.Specifically the transition between the internal circumference of thepressure sleeve and the abutting face exhibits a radius or a chamfer.For example, the radius is between 1 mm and 2 mm, specifically 1.5 mm.

It is preferable that the inside diameter of the first shoulder of theinner body is smaller than the outside diameter of the second shoulderof the pressure sleeve, so that the first shoulder and second shoulderat least partially overlap radially. It is thereby ensured that movementof the pressure sleeve in the direction of the valve tappet head can belimited by the first shoulder, whereby the force from the pressuresleeve upon the valve tappet head can be limited.

A further iteration of the coupling element provides that the firstlimit stop and the second limit stop are distanced from one another atleast in an unpressurized condition; uncoupled condition. It ispreferable that the length of the pressure sleeve be chosen so that in aclosed condition the pressure sleeve contacts the valve tappet head,whereby the first and second limit stops are simultaneously distancedfrom one another.

Increasing pressure within the flow channel leads to stretching of thevalve tappet, particularly in the area of the shaft, and an expansion ofthe pressure sleeve, whereby beyond a specific threshold pressure valuewithin the flow channel, both effects lead to the first limit stop andthe second limit stop coming into contact with one another and theoccurrence of a partial transfer of force to the inner body, as a resultof which the force of the pressure sleeve upon the valve tappet head islimited. It is preferable that this threshold value lies within a rangebetween operating pressure and four times operating pressure,specifically between 1.5 and 2 times operating pressure, wherebyoperating pressure ideally lies between 25 MPa and 40 MPa.

The first limit stop and the second limit stop are thus designed andarranged so that the force is limited, at least beyond a predeterminedpressure within the flow channel, specifically a pressure between 35 MPaand 70 MPa. The first limit stop and the second limit stop thus comeinto play in this iteration only after a predetermined pressure withinthe flow channel is exceeded. Before that, i.e. with lower pressureinside the flow channel, pressure that is below the threshold value,specifically below 35 MPa, the first limit stop is not in contact withthe second limit stop, and the pressure sleeve is supported exclusivelyby the valve tappet head.

A further iteration thus provides for the first limit stop and thesecond limit stop to come into play at least at a predetermined pressurewithin the flow channel in the event of a pressure-related deformationof the valve tappet and/or the pressure sleeve. The pressure at which anelastic and/or plastic deformation of the components takes place variesdepending upon the materials from which the valve tappet, the pressuresleeve, and the inner body are constructed. In any case, the materialsare so chosen that beyond a predetermined pressure, the valve tappetand/or the pressure sleeve are deformed in such a way that the firstlimit stop and second limit stop come into play, whereby the force uponthe valve tappet head is limited. It is preferable that the deformationof the valve tappet, the pressure sleeve, and the inner body takes placein an elastic manner. Only in the event of an unintentional overload ofthe coupling element do the components deform in a plastic manner, whichultimately leads to leakage in the area between the pressure sleeve andthe valve tappet head. As already described, this pressure is betweenthe operating pressure and fourfold operating pressure, specificallybetween 1.5 and 2 times operating pressure.

A favorable seal between the pressure sleeve and the valve tappet headis achieved in a further iteration in that the valve tappet headexhibits a sealing surface and the sealing surface is pitched at angle αin relation to coupling axis A. It is preferable that angle α is between0° and 45°. The sealing surface is a partial surface on the rearwardside of the valve tappet head. Furthermore, the pressure sleeve exhibitsan opposing sealing surface, which is pitched at angle β in relation tocoupling axis A. It is preferable that angle β lies between 0° and 45°,specifically between 25° and 40°. The opposing sealing surface is atleast in partial contact with the first sealing surface when thepressure sleeve is in its closed position, so that the opposing surfacescreate a seal. Specifically, the opposing sealing surfaces facilitatethe transfer of forces parallel to coupling axis A from the pressuresleeve onto the valve tappet head. Furthermore, a seal is providedbetween the valve tappet head and the pressure sleeve which connects tothe sealing surface and rests on the inner circumference of the pressuresleeve in the closed position.

A conical seal such as this between the valve tappet head and thepressure sleeve has the advantage that even with a short stroke of thepressure sleeve, the flow channel is opened, which reduces the flowlosses in the coupling. Additionally, the conical seal is simple androbust against tolerance variations. Another advantage is that the gapwhich is provided for a seal on the low-pressure side of the valvetappet head can be minimized or completely closed with a conical sealbetween the valve tappet head and the pressure sleeve, even whenutilizing normal production tolerances.

A favorable seal can also be achieved when angles α and β are identical,i.e. the opposing sealing surfaces are angled identically so that theopposing sealing surfaces rest at least partially flat against oneanother in the closed position. It is preferable that α and β haveangles between 25° and 35° for this purpose, particularly 30°.

The sealing effect can also be increased when it is provided that α andβ are different. It is preferable that α is smaller than β. Then theopposing sealing surface rests on an edge of the first sealing surface,with the result that tolerances are balanced and a gap on thelow-pressure side is avoided. It is preferable that α is between 0° and35° and β is between 30° and 45°. In a design in which the sealingsurface extends parallel to coupling axis A, with α=0° and β=for example30°, the opposing sealing surface rests only on a circumferential edgeof the sealing surface when in closed position.

The valve tappet can be advantageously mounted within the couplingelement when it is provided in a further iteration that the valve tappetis held in a tappet bearing on the housing, and that the tappet bearingincludes at least two half-shells. The valve tappet exhibits acircumferential groove on its shaft, into which the half-shells can beat least partially inset. Subsequently the valve tappet with the insethalf-shells is mounted within the housing, specifically in such a mannerthat the valve tappet is held between the inner body and the connectingcomponent.

It has also proven advantageous for operating safety if the tappetbearing is located in a groove on the valve tappet, whereby the grooveexhibits two opposing groove walls and a groove base. The groove wallsare preferably oriented orthogonally to coupling axis A, and the groovebase oriented parallel to the axis. Between the groove base and at leastone of the groove walls, i.e. in the area of the transition from thegroove wall to the groove base, at least one chamfer with angle γ tocoupling axis A is provided. It is preferable that at least one chamferis provided between the groove wall facing away from the valve tappethead and the groove base. It is preferable that angle γ is between 30°and 60°. It is especially preferable that the chamfer has angle γ of 35°with a width of 0.45 mm (35°×0.45). For example, a radius is providedbetween the groove wall on which there is no chamfer and the groovebase.

Specifically it is also provided that at the transition from each of thetwo groove walls to the groove base, there is at least one chamfer withangle γ to coupling axis A or to the longitudinal axis of the valvetappet coinciding with coupling axis A.

Through the provision of this at least this one chamfer, the tension inthe groove base upon loading of the valve tappet is markedly reduced,whereby operating safety is increased and/or operating parameters areincreased.

The tension in the groove base can be further reduced when it isprovided in accordance with a further iteration that an additionalsecond chamfer with angle (δ) to coupling axis A is added between atleast one of the two groove walls and the groove base, and that thesecond chamfer originating from the groove wall connects to the firstchamfer. Originating from the groove wall, the transition to the groovebase is initially composed of the first chamfer and subsequently thesecond chamfer. For example, the first chamfer and the second chamferare imagined on the groove wall facing away from the valve tappet head.It is preferable that angle γ of the first chamfer is greater than angleδ of the second chamfer. Specifically, angle δ is between 30° and 60°.Furthermore it is especially preferable that in the transitional regionof at least one groove wall to the groove base, at least a third chamferor at least a fourth chamfer be provided.

For example it is also provided that in the transitional region of bothgroove walls to the groove base, at least a first chamfer and at least asecond chamfer are provided on each side.

The loss of pressure medium during the coupling process of a couplingwith a coupling element can be easily reduced when it is provided thatthe coupling element is designed to be flat-sealing; that is allcomponents of the coupling element lie in one plane on the second end ofthe coupling element. Thus the intrusion of dirt is prevented, cleaningof the coupling element is simplified, and the loss of pressure mediumis minimized.

Particularly advantageous is the use of the coupling element in acoupling, especially a hydraulic coupling.

The initially cited objective is further met with an inventive valvetappet in which the valve tappet exhibits a groove with two groove wallsand a groove base, wherein at least a first chamfer is provided betweenat least one of the groove walls and the groove base.

BRIEF DESCRIPTION OF THE DRAWINGS

Specifically, there is now a plurality of possibilities for designingand further developing the coupling element. This is referenced in thesubsequent description of the selected design examples in associationwith the illustration. The illustration shows:

FIG. 1 A design example of a coupling element in a sectional side view,

FIG. 2 The design example of the first coupling element in accordancewith FIG. 1 in another operating state, and a design example of a secondcoupling element in a sectional side view,

FIG. 3a A section of the design example in accordance with FIG. 1 in thearea of the valve tappet head,

FIG. 3b A section of a design example of a coupling element in the areaof the valve tappet head,

FIG. 3c A section of a design example of a coupling element in the areaof the valve tappet head,

FIG. 4 A section of the design example in accordance with FIG. 1 in thearea of the tappet guide,

FIG. 5 A section of a design example of a valve tappet for a couplingelement,

FIG. 6a A section of a design example of a valve tappet for a couplingelement, and

FIG. 6b A section of a design example of a valve tappet for a couplingelement.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

FIG. 1 shows a design example of a coupling element 1, which is designedas a coupling sleeve. The coupling element 1 is a part of a coupling forconnecting pressure medium lines, in this example a hydraulic couplingThe coupling element 1 shown, the coupling sleeve, serves to join with acorresponding second coupling element 1 a; shown in FIG. 2; a couplingplug, whereby two pressure medium lines, one with the coupling sleeveand one with the coupling plug, can be connected to one another.

Coupling element 1 includes a housing 2, whereby the housing 2 includesa connecting component 3 as well as a sliding sleeve 4. The housing 2limits at least partially a flow channel 5 for a pressure medium. Withinthe flow channel 5, a valve tappet 6 is centrally located. The valvetappet 6 is surrounded by a pressure sleeve 7. The pressure sleeve 7 ismovable within an inner body along a coupling axis A.

The valve tappet 6 located centrally in the flow channel 5 exhibits avalve tappet shaft 9 and a valve tappet head 10. The valve tappet head10 is flared out in comparison to the valve tappet shaft 9, and thusexhibits a larger diameter. The pressure sleeve 7 is fitted within theinner body 8 in such a manner that the pressure sleeve 7 is movablealong coupling axis A between a closed position, in which the flowchannel 5 is closed by the pressure sleeve 7, and an open position, inwhich the flow channel 5 is opened by the pressure sleeve 7.

In the unpressurized closed position shown in FIG. 1, the pressuresleeve 7 is in contact with the valve tappet head 10, whereby a forceparallel to coupling axis A from the pressure sleeve 7 acts upon thevalve tappet head 10. Additionally, a seal 11 is located between thevalve tappet head 10 and the pressure sleeve 7, which is located in acorresponding groove 12 in the valve tappet head 10. The valve tappethead 10 constitutes a part of the flat-sealing abutting face of thecoupling element shown in FIG. 1 at the right-hand side. Theflat-sealing abutting face of the coupling element 1 is composed furtherof a piston 13, a base body 14, and the sliding sleeve 4.

The pressure sleeve 7, which is displaceably held within the inner body8, is constantly pushed in the direction of its closed position by acompression spring 15, so that the pressure sleeve 7 is only movable outof its closed position against the force of the compression spring 15.The compression spring 15 also surrounds the valve tappet 6, when thepressure sleeve 7 is in contact with the valve tappet 6, specificallythe valve tappet head 10, a force parallel to coupling axis A is exertedfrom the pressure sleeve 7 upon the valve tappet head 10. Specifically,this force consists of the force of the compression spring 15 and apressure-dependent component, namely the effect of the pressurizedpressure medium on the pressure medium line 7. Under very highpressures, the forces acting upon the valve tappet 6 can lead to damageto the valve tappet 6.

In order to prevent this, the inner body 8 and the pressure sleeve 7have features with which the forces from the pressure sleeve 7 upon thevalve tappet head 10 can be limited, namely a first circumferentialshoulder 16 on the inner body 8 and a second circumferential shoulder 17on the pressure sleeve 7. The first shoulder 16 exhibits a first limitstop and the second shoulder 17 exhibits a second limit stop. When thefirst shoulder 16 contacts the second shoulder 17, a transfer of forcetakes place from the pressure sleeve 7 to the inner body 8, by which theforce from the pressure sleeve 7 acting upon the valve tappet head 10 islimited.

The second shoulder 17 is located in the end region of the pressuresleeve 7 that is oriented in the direction of the release position ofpressure sleeve 7. The second shoulder 17 includes the abutting face 32of the pressure sleeve 7 which is oriented in this direction. Betweenthe inside circumference of the pressure sleeve 7 and the abutting face32 is a radius 33, which improves the flow characteristics of thepressure sleeve 7.

In the unpressurized closed position of the coupling element 1illustrated in FIG. 1; no pressurized pressure medium in the flowchannel; the stop face 18 of the first shoulder 16 is spaced apart fromthe stop face 19 of the second shoulder 17 in a longitudinal direction,that is in a direction parallel to coupling axis A. As pressureincreases within the flow channel 5, the valve tappet shaft 9; amongother parts; stretches due to the pressurized pressure medium, wherebythe pressure sleeve 7 expands. Due to this effect, the first stop face18 of the first shoulder 16 comes into contact with the second stop face19 of the second shoulder 17, whereby force is transferred from thepressure sleeve 7 to the inner body 8 and the force exerted by thepressure sleeve 7 upon the valve tappet head 10 is limited, in that apart of the force is dissipated by the inner body 8. This state isillustrated in FIG. 2 for example.

The force exerted by the pressure sleeve 7 upon the valve tappet head 10is thus limited in at least one operating state, particularly when atleast one threshold pressure value within the flow channel 5 isexceeded, and specifically distributed between the valve tappet head 10and the inner body 8. As the first shoulder 16 and the second shoulder17 are circumferential in form, the force can be advantageouslydistributed across the entire ring face.

In its closed position, the pressure sleeve 7 contacts the valve tappethead with its conical opposing sealing surface 34, so that between thepressure sleeve 7 and the valve tappet head 10 there is a conical seal.The details of the system can be found in FIG. 3a and the associateddescription.

Furthermore, a seal 20 is placed between the pressure sleeve 7 and theinner body 8. The seal 20 is located in a groove 30, which is located onthe inner body 8 between the first shoulder 16 and a sealing shoulder31. The sealing shoulder 31 includes the abutting face of the inner body8 which is oriented in the direction of the valve tappet head 10.

The inner body 8 is braced between the base body 14 and the connectingcomponent 3, whereby a seal 21 is located between the inner body 8 andthe connecting component 3.

The valve tappet 6 is held on the housing 2 by a valve tappet bearing23, specifically it is braced between the inner body 8 and theconnecting component 3. The valve tappet bearing 23 includes twohalf-shells, which engage with a groove 24 on the valve tappet 6 andthus hold the valve tappet 6 centrally in the flow channel 5. Thecompression spring 15 for the pressure sleeve 7 is supported on thevalve tappet bearing 23 in order to exert a force on the pressure sleeve7 in the direction of its closed position. The details of a valve tappet6 in the area of the valve tappet bearing 23 can be found in FIG. 4.

A piston spring 25 is located between the inner body 8 and the base body14 which is screwed to the connecting component 3, which holds thepiston 13 in its closed position in the flat-sealing abutting face ofcoupling element 1. In the closed position, the piston 13 blocksmovement of the retaining balls 26, which themselves block the slidingsleeve 4 in its open position. The sliding sleeve 4 is pressed againstthe retaining balls 26 by a sleeve spring 27.

When the coupling element 1, here a coupling sleeve, is connected to acorresponding coupling element 1 a, for example the coupling plug—(seeFIG. 2), the piston 13 is pushed against the force of the piston spring25 into the interior of the coupling element 1, whereby movement of theretaining balls 26 is enabled. The retaining balls 26 then move into anoutside circumferential groove 39; illustrated in FIG. 2; on thecorresponding coupling element 1 a. The sliding sleeve 4 thereby movesin the direction of its locked position, in which movement of theretaining balls 26 is in turn blocked by a keepout area 28 of thesliding sleeve 4 in such a manner that a positive connection is madebetween the first coupling element 1 and the second coupling element 1 aby the retaining balls 26. In the locked position, the sliding sleeve 4contacts a blocking element, which is implemented here as a circlip 29.The sliding sleeve 4 is always loaded by the sleeve spring 27.

FIG. 2 shows the design example of the first coupling element 1 inaccordance with FIG. 1 in another operating state, specifically in thestate in which the first shoulder 16 of the inner body 8 and the secondshoulder 17 of the pressure sleeve come into play. In this operatingcondition, present in the event of pressure of approximately 40 MPa, theforce from the pressure sleeve 7 upon the valve tappet head 10 islimited by the first shoulder 16 and the second shoulder 17, in that apart of the force is conveyed to the inner body 8. In FIG. 2 the firstshoulder 16 and the second shoulder 17 are in flat contact with oneanother.

Furthermore, FIG. 2 shows a design example of a second coupling element1 a, which here is designed as a coupling plug. The second couplingelement 1 a includes a plug body 40, in which a plunger 42 loaded with aspring 41 is located. An outside circumferential groove 39 is located onthe plug body 40, which interacts with the retaining balls 26 of thefirst coupling element 1. In the state illustrated, the plunger 42closes the flow channel 43. The second coupling element 1 a can beinserted into the first coupling element 1, in that the plug body 40 isinserted into the first coupling element 1 in such a manner that thepiston 13 is pushed into the interior of the first coupling element 1against the force of the piston spring 25, whereby beyond a certainposition the pressure sleeve 7 is pushed by the piston 13 in thedirection of its open position.

In the operating state of the first coupling element 1 depicted in FIG.2, however, insertion of the second coupling element 1 a would beimpossible, as the pressure in the flow channel 5 is too high.

FIG. 3a shows a section of the design example according to FIG. 1 in thearea of the valve tappet head 10. The valve tappet head 10 exhibits asealing surface 22, which is pitched at an angle α of 30° in relation tocoupling axis A. Furthermore, the pressure sleeve 7 exhibits an opposingsealing surface 34, which is also pitched at an angle β of 30° inrelation to coupling axis A. The opposing sealing surface 34 is thusimplemented as a chamfer on the pressure sleeve 7. In that the sealingsurface 22 and the opposing sealing surface 34 have identical angles tocoupling axis A, the pressure sleeve 7, in its closed position asdepicted, rests with sealing surface 34 at least partially flat onsealing surface 22, whereby a longitudinal force is directly transferredfrom the pressure sleeve 7 to the valve tappet head 10. For furthersealing, the seal 11 is provided, which is located in a groove 12 in thevalve tappet head 10 of the valve tappet 6.

FIG. 3b shows a section of a design example of a coupling element in thearea of the valve tappet head 10. The sealing surface 22 has an angle αof 0° (a in FIG. 3b is not depicted), so that the sealing surface 22 isoriented parallel to coupling axis A. The opposing sealing surface 34 ofthe pressure sleeve 7 exhibits an angle β of 35° to coupling axis A, sothat in the depicted closed position the pressure sleeve 7 makes contactonly on an edge of sealing surface 22, whereby an advantageous sealingeffect between the pressure sleeve 7 and the valve tappet head 10 iscreated. For further sealing effect, a seal 11 is provided in a groove12 in the valve tappet head 10 of the valve tappet 6.

FIG. 3c shows a section of a further design example of a couplingelement 1 in the area of the valve tappet head 10 of the valve head 10.The sealing surface 22 exhibits an angle α of 30° to coupling axis A,while the opposing sealing surface 34 exhibits an angle β of 35° tocoupling axis A. In the closed state depicted, the pressure sleeve 7thus makes contact with the opposing sealing surface 34 only on acircumferential edge of sealing surface 22. Additionally, for furthersealing effect, a seal 11 is provided in a groove 12.

FIG. 4 shows a section of the design example according to FIG. 1 in thearea of the groove 24 for attachment of valve head 10. The tappet guide23 is located in the groove 24. The tappet guide 23 is fixed between theinner body 8 and the connecting component 3. The seal 21 is locatedbetween the inner body 8 and the connecting component. The groove 24exhibits two opposing groove walls 35 a and 35 b which transition intothe groove base 36 by way of a first chamfer 37. Due to the firstchamfer 37, the tension on the groove base 36 in operating state ismarkedly reduced, which clearly increases operating reliability. Eachfirst chamfer 37 is oriented opposite the other, inclined at an angle ofapproximately 35° to coupling axis A, and exhibits a width of 0.45 mm.

FIG. 5 shows a design example of a valve tappet 6 for a coupling element1. The groove 24 with its opposing groove walls 35 a and 35 b as well asthe groove base 36 is depicted. Next to the first chamfer 37 in thetransition between the groove walls 35 a/35 b, a second chamfer isadded, which is located adjacent to the first chamfer 37. The firstchamfer 37 and the second chamfer 38 have different angles ofinclination to coupling axis A. The first chamfer 37 has an angle γ of45° to coupling axis A, while the second chamfer 38 has an angle δ of30° to coupling axis A.

FIG. 6a shows a design example of a valve tappet 6 for a couplingelement 1. The groove 24 with its opposing groove walls 35 a and 35 b aswell as the groove base 36 is depicted. In the transition between thegroove wall 35 a facing away from the valve tappet head 10, not depictedin FIG. 6a , a second chamfer 38 is located next to the first chamfer37, the second chamfer abutting directly on the first chamfer 37. Thefirst chamfer 37 and the second chamfer 38 have different anglesrelative to coupling axis A or to the longitudinal axis of the valvetappet that coincides with it. The first chamfer 37 exhibits an angle γof 45° to coupling axis A, while the second chamfer 38 exhibits an angleδ of 30° to coupling axis A.

FIG. 6b shows a design example of a valve tappet 6 for a couplingelement 1. The groove 24 with its opposing groove walls 35 a and 35 b aswell as the groove base 36 is depicted. In the transition between thegroove wall 35 a facing away from the valve tappet head 10, not depictedin FIG. 6a but located on the left side, a first chamfer with an angle γis located. The first chamfer 37 has an angle γ of 45° to coupling axisA or to the longitudinal axis of the valve tappet 6 that coincides withit.

While the above description constitutes the preferred embodiment of thepresent invention, it will be appreciated that the invention issusceptible to modification, variation and change without departing fromthe proper scope and fair meaning of the accompanying claims.

1. A coupling element for a coupling for connection of pressure mediumlines, comprising a housing, a flow channel for a pressure medium, avalve tappet, a pressure sleeve and an inner body, wherein the housinghas a coupling axis A, wherein the valve tappet is mounted in thehousing such that the valve tappet is arranged in the flow channel,wherein the valve tappet has a valve tappet head, wherein the pressuresleeve surrounds the valve tappet, wherein the pressure sleeve is heldin a movable configuration along the coupling axis A between a closedposition, in which the flow channel is closed by the pressure sleeve,and an open position, in which the flow channel is opened by thepressure sleeve, wherein the pressure sleeve is in at least indirectcontact with the valve tappet head when in the closed position, whereina force from the pressure sleeve parallel to the coupling axis A actsupon the valve tappet head, further comprising wherein the inner body orthe pressure sleeve has means with which the force from the pressuresleeve upon the valve tappet head can be limited.
 2. A coupling elementin accordance with claim 1, further comprising the means on the innerbody is formed as a first limit stop, and the means on the pressuresleeve is formed as a second limit stop, wherein the first limit stopand the second limit stop interact for limiting the force.
 3. A couplingelement in accordance with claim 2, further comprising, the first limitstop is formed as a first shoulder on the inner body and the secondlimit stop is formed as a second shoulder on the pressure sleeve.
 4. Acoupling element in accordance with claim 3, further comprising, theinside diameter of the first shoulder of the inner body is smaller thanthe outer diameter of the second shoulder of the pressure sleeve.
 5. Acoupling element in accordance with claim 2, further comprising, thefirst limit stop and the second limit stop are spaced apart from oneanother at least in the unpressurized closed position of the pressuresleeve.
 6. A coupling element in accordance with claim 2, furthercomprising, the first limit stop and the second limit stop make contactat least beyond a predetermined pressure within the flow channel due toa pressure-related deformation of the valve tappet or the pressuresleeve.
 7. A coupling element in accordance with claim 1, furthercomprising, the valve tappet head has a sealing surface that is titledat an angle α to the coupling axis A, that the pressure sleeve has anopposing sealing surface, that the opposing sealing surface is titled atan angle β to the coupling axis A, that the opposing sealing surface atleast partially contacts the sealing surface in the closed position ofthe pressure sleeve, and that the angles α and β lie between 0° and 45°.8. A coupling element in accordance with claim 7, further comprising,the angles α and β are identical, specifically that the angles α and βlie between 25° and 35°.
 9. A coupling element in accordance with claim7, further comprising, that the angles α and β are different,specifically the angle α is between 0° and 35° and the angle β isbetween 30° and 45°.
 10. A coupling element in accordance with claim 1,further comprising, the valve tappet is held on the housing by a tappetbearing, and that the tappet bearing comprises at least two half-shells.11. A coupling element in accordance with claim 10, further comprising,the tappet bearing is located in a groove on the valve tappet, that thegroove has two opposing groove walls and a groove base, and that betweenat least one of the groove walls and the groove base there is at least afirst chamfer forming having an angle γ to the coupling axis A, theangle γ is between 30° and 60°.
 12. A coupling element in accordancewith claim 11, further comprising, between at least one groove wall ofthe two groove walls and the groove base, additionally at least onesecond chamfer is formed having an angle δ to the coupling axis A, andthat the second chamfer emanating from the groove wall connects to thefirst chamfer, the angle δ is between 30° and 60°.
 13. A couplingelement in accordance with claim 1, further comprising, the couplingelement is formed as coupling sleeve or as coupling plug.
 14. Ahydraulic coupling, with a first coupling element, and a second couplingelement, wherein the first coupling element and the second couplingelement are formed in accordance with claim
 1. 15. A valve tappet forthe coupling element, specifically in accordance with claim 1, with avalve tappet shaft and a valve tappet head, wherein a groove is providedfor receiving a tappet bearing, wherein the groove has two opposinggroove walls and a groove base, further comprising, between at least oneof the groove walls and the groove base there is at least a firstchamfer with an angle γ to the longitudinal axis A of the valve tappet,the angle γ is between 30° and 60°.
 16. A valve tappet for couplingelement in accordance with claim 15, further comprising, between the atleast one groove wall of the two groove walls and the groove baseadditionally, at least one second chamfer with an angle δ to thecoupling axis A is formed, and that the second chamfer emanating fromthe groove wall connects to the first chamfer, angle δ is between 30°and 60°.